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Study on Long-Term Safety and Effects of DNL310 for Patients with Mucopolysaccharidosis Type II (MPS II)

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the long-term effects of a treatment called DNL310 in patients with Mucopolysaccharidosis Type II, also known as MPS II. MPS II is a rare genetic disorder that affects the body's ability to break down certain complex molecules, leading to various health issues. The treatment being tested, DNL310, is a special type of protein designed to help manage the symptoms of MPS II. It is given as a solution through a vein, a method known as intravenous infusion.

The purpose of this study is to evaluate how safe and tolerable DNL310 is for patients over a long period. Participants in this study will receive the treatment and be monitored for any side effects or changes in their condition. The study will also look at how the treatment affects certain substances in the body, like glycosaminoglycans, which are complex sugars that build up in patients with MPS II. Additionally, the study will assess changes in physical abilities, such as walking distance, and organ sizes, like the liver and spleen, using imaging techniques like MRI.

This study is an extension of previous research, meaning it continues to follow patients who have already participated in earlier studies of DNL310. The goal is to gather more information about the treatment's long-term effects and benefits for those living with MPS II. Participants will be involved in the study for several years, allowing researchers to collect comprehensive data on the treatment's impact over time.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Participation begins after completing the required duration in a previous study. This includes at least 49 weeks in Study DNLI-E-0002 or 96 weeks in Cohort A and 48 weeks in Cohort B of Study DNLI-E-0007.

  2. Step 2

    Treatment administration

    The treatment involves the administration of DNL310, a solution for infusion. This is given through an intravenous route, meaning it is delivered directly into the bloodstream through a vein.

  3. Step 3

    Monitoring and assessments

    Throughout the treatment period, which lasts up to 5 years, the focus is on monitoring the safety and tolerability of the treatment. This includes tracking any adverse events and reactions related to the infusion.

    Regular assessments are conducted to measure changes in urine glycosaminoglycan (GAG) concentrations, which are substances that can accumulate in the body due to MPS II.

  4. Step 4

    Secondary evaluations

    Additional evaluations include measuring changes in cerebrospinal fluid (CSF) heparan sulfate (HS) concentration, cognitive scores, and physical abilities such as walking distance.

    Imaging tests like MRI are used to check liver and spleen volumes, ensuring they remain within normal ranges.

  5. Step 5

    Completion of study

    The study is expected to conclude by July 15, 2027. The primary goal is to gather comprehensive data on the long-term effects of the treatment on patients with MPS II.

Who can join the trial?

6 criteria

  • The study is for patients with a condition called Mucopolysaccharidosis Type II, also known as MPS II.
  • Participants must have completed certain previous studies:
  • If you were in Study DNLI-E-0002, you must have completed at least up to the Week 49 visit and not stopped the study treatment early.
  • If you were in Study DNLI-E-0007, you must have completed the treatment period of 96 weeks in Cohort A for those with nMPS II, or 48 weeks in Cohort B for those with nnMPS II.
  • The study is open to both male and female participants.
  • The study includes participants from a vulnerable population, which means people who might need extra protection or care.

Who cannot join the trial?

8 criteria

  • Patients who have a medical condition other than Mucopolysaccharidosis Type II (MPS II). MPS II is a rare genetic disorder that affects the body's ability to break down certain substances.
  • Patients who are not within the specified age range for the study. The study is open to certain age groups only.
  • Patients who are not able to follow the study procedures or instructions.
  • Patients who have any other health issues that might interfere with the study or make it unsafe for them to participate.
  • Patients who are currently participating in another clinical trial or have recently participated in one.
  • Patients who are pregnant or breastfeeding, as the study may not be safe for them or their baby.
  • Patients who have a history of allergic reactions to the study medication or similar medications.
  • Patients who have a history of drug or alcohol abuse, which might affect their ability to participate in the study.
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Investigated drugs

DNL310 is a medication being studied for its long-term safety, tolerability, and effectiveness in patients with Mucopolysaccharidosis Type II (MPS II). This condition is a rare genetic disorder that affects the body's ability to break down certain sugars. The trial aims to understand how well patients can tolerate this medication over an extended period and to observe any potential side effects or improvements in their condition.

What is already known about the treatment

DNL310 – DNL310 is administered intravenously, meaning it is given directly into a vein. It is currently being studied in clinical trials to evaluate its long-term safety, tolerability, and effectiveness for treating Mucopolysaccharidosis Type II (MPS II), a rare genetic disorder. The medication is designed to address the underlying enzyme deficiency in MPS II by delivering a modified enzyme that can cross the blood-brain barrier, potentially improving both central nervous system and peripheral symptoms. DNL310 is classified as an enzyme replacement therapy, aiming to supplement or replace the missing or deficient enzyme in affected individuals.

Investigated diseases

Mucopolysaccharidosis Type II – Mucopolysaccharidosis Type II, also known as Hunter syndrome, is a rare genetic disorder caused by a deficiency of the enzyme iduronate-2-sulfatase. This enzyme deficiency leads to the accumulation of glycosaminoglycans in various body tissues, causing progressive damage. Symptoms often include developmental delays, distinctive facial features, and joint stiffness. Over time, individuals may experience hearing loss, heart problems, and respiratory issues. The disease primarily affects males and symptoms can vary widely in severity. As the condition progresses, it can impact the central nervous system and other vital organs.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-503837-23-00Protocol codeDNLI-E-0008Estimated enrolment109 patientsSponsorDenali Therapeutics Inc.

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

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